We just want to give you a convenient way to update the firmware without having to think about which bootloader to use and how to jumper BOOT0&BOOT1.
Also, if your board is already installed in the machine, the jumper setting is more inconvenient for you.
So, by adding a chip that can solve the problem, why not do it?

At the time of design, we thought that plugging in the USB is just to update the firmware, and at other times you will use the SD card for printing. Even if you use USB printing, it should be a short-time debugging.
Even, we found that most of the 2560 boards did the same, and nothing went wrong. This should be a way of testing over time.
Until TH3D promotes this problem in the whole world, I think this will cause confusion for many people, so I will solve this problem whether or not it will cause problems, and it was already solved on the 1.2a version.

First of all, this is not a hardware problem, we can adjust it through software, and it is very easy.
Secondly, there is no fixed standard in this direction, and different people may not like the same.
Finally, we have changed to the most favorite way, if you want to reverse, you can also set the firmware yourself.
Note: In fact, our price is only the price of a hardware platform, we have never calculated the value of software, we think that as one of the contributors and users of marlin, we should follow the spirit of open source, make more people easier Get the convenience of open source. Instead of selling it with open source resources.

First of all, we should know that low-voltage signals are easily interfered, so we should try to avoid the screen line and the high-voltage and high-current lines being too close.
In addition, our people usually have static electricity on their hands, and directly touch some electronic components, which may also affect normal signal transmission.
So if it is just an accidental phenomenon and it will disappear after re-power, then don't worry.
If it has been there, please contact us and we will deal with it according to the specific situation!

This is a firmware issue that has been fixed so far, you can fix it by upgrading the firmware.
For new firmware,the default config is not for cheetah board anymore as we have other boards to release and the need to build the firmware, you need to change default_envs to fysetc_STM32F1 in platformio.ini file and replace the configuration.h and configuration_adv.h file with FYSETC example config.